Survey and Plan for Irrigation Development in the Pangani and Wami River Basins Project Area,1967
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URT/S-1 FAOISF:421TAN-4 X AND PLAN FOR IRAIGATIO:1 DEVELOPME T F THE PANCJANI A WAMI RIVE- BASINS In E r'iNAL REPORT UNITED NATIONS DEVELOPMENT PROGRAMME VI lyV FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS Fo0 V 4, rev" R MaroUSOMA o rfirreti FOr o o 10° o 100 200 300 M I es Internationalborderes Roads Railways 2WProject area PANGANI--;TI RIVE. rASINS SURVEY AND PLAN FOR IRRIGATION DEVELOPMaNT IN THE PANGANI AND WAMI RIVER BASINS UNITED REPUBLIC OF TANZANIA K m ()CATION OF TANZANIA IN AL: VA FAO/SF:11- /TAN4 Survey and Plan for IrrigationDevelopment In the Pangani and Wami River Basins UNITED L BLIC OF TANZANIA FinalReport Report prepacod the Government of Taw..ani by the Food and Agriculture Organiziltion of tho United Nations aoting as executing agoncy for theUnitedNations Development Programme JNITED NATIONS DEVELOPMENT PROGRAMME FOOD AND AGRICULTURE ORGANIZATION OP THE UNITED NATIONS Rome, 1969 vii ABSTRACT The accompanying report describes a project undertaken by the Government of the United Republic of Tanzania, with the assistance of the United Nations Development Programme1/,to investigate the potential for irrigation development in the Pangani and Wami river basins, to prepare detailed plans and work schedules for pilot areas, and to draw up programme of irrigation development for execution in the seven years following the completion of the projeot. The need for the development in the Pangani and Wami river basins is part of the need for improvement of the national and regional economy, but particularly arises from the pressure of population in the upper Pangani basin. The Governmentts request for assistance was approved by the Governing Council of the United Nations Special Fund in January1964. The Food and Agrioulture Organization of the United Nations was appointed the Exeouting Agenoy, and the Ministry of Agrioulture was appointed as the Government Cooperating Agency2/. The UNDP contribution to the project 'as in the form of professiond and technical personnel, contractual services, equipment and supplies to the value of $ 1 225 300, and this was matched by the Government counterpart contribution in kind estimated at 921 000. During the execution of the project aerial photography of part of the Wami coastal plain was carried out by contractors AeroPreoisa of Lebanon, and of the Wami escarpment area by Messrs. Story and Partners. The other surveys and investigations were carried out by internationally recruited experts and Govern- ment counterpart personnel. 11/ Assistance to the project was provided by the United Nations Special Fund until 1st January1966. On that date the Special Fund and the Expanded Programme of Technioal Assistance were merged into the United Nations Development Programme which oontinued to provide assistanoe to the projeoti 2/ Ministerial reorganization led to the Government Cooperating Agenoy being changed from the Ministry of Agrioulture to the Ministry of Lands, Settlement, and viater Development. viii It is estimated that in the headwatere region of the Pangani approximately 300 000 acres are under some form of irrigation and that about 500 000 acre,feet of water aro currently abstraoted annually from various tributaries, largely for irrigation. Mainly duo to unsuitable soils the potential for expansion of irrigation in the Pangani baein is limited. Four areas, totalling some 20 000 acres are proposed for development. The form of development proposed inoludes the improvement and intensifioation of emisting irrigation farming, as well as development by settlement of unused, or largely unused, areas. On the Wami coastal plain consideration is given to irrigation development on some 50 000 acres. Flood control, however, is essential before major irriga- tion development can take place, and land development costs for irrigation are too high for irrigation to bear any part of the costs of the neceesary flood control reservoir.M jor irrigation development, therefore, cannot take place unless and until a decision is taken to develop the hydroelectric power potential of the Wami. An order of priority for irrigation development is suggested, and it ie proposed that early attention shouldbe given tothose areas where improvements and intensification of ceristing irrigation can be effected. Pilot areas are recommended for each of the proposed main development areas, two of which have been established, and a detailed engineering design has been prepared for a third. Proposals for future work on the pilotareas arosubmitted, and it is stressed that development based on settlement ehould not oommonce until farming systems have been fully tested on the pilot execi.sp managerial and administrativo problems studied, and the neoessary infrastructure and supporting services can be provided. Pmphsin Is g*ven 'botho nood. foy' soordinr,tion of all with sectorial Uto,vonto jn urr ns.go2 nnel. ho demi.rvhAjty of a unified irrigation development oll;hoy to onnrys ;'1131 socrodtpationo - ix TABLE OF CONTENTS Page No. CHAPTER I INTRODUCTION 1 The Background 1 The Plan of Operation 2 Hydroelectric Power 7 4, Brief Account of Execution 8 Reports 13 Acknowledgements 13 CHAPTER II SUIZ1ARY OF CONCLUSIONS AND RECOMIMIDATIONS 15 A. THE CONCLUSIONS OF nib SURVEY 15 General 15 Land and Water Resources 16 Markets 18 Irrigation Development 18 Pilot Irrigation Areas 20 Health 21 Hydroelectric Power 21 B. RECOMIZNDATIONS 21 Irrigation Development 22 Processing 24 Establishment of a Unified Irrigation 24 Development Authority Training 25 Health 25 CHAPTER III DESCRIPTION OF PROJECT 27 General 27 Location and Physical Description 27 Climate 30 Communications 30 Land Use and the People 31 Health 33 Táze No. CHAPTER IV SOIL SURVEYSAND SUITABILITY FOR IRRIGATION 35 General Introduction 35 Summary of Findings in Pangani Headwater 41 Region Summary of Findings in the Middle Pangani 42 Region Summary of Findings in the Wami Coastal 48 Plain CHAPTER V CLIMATOLcGY AND HTDROLOGY 55 Climatological and Hydrological Data 55 Climatology of the River Basins 56 Hydrology 66 CHAPTER VI WATER CONTROL ! USAGE 71 Background and Present Situation 71 Hater Control and Storage 72 Proposed Irrigation Use 74 Water Use in the Pangani River Basin 76 Hydroelectric Power Development 78 CHAPTER VII IRRIGATION 77 :1777ERING 89 Kahe lirigation Scheme 89 Mivaleni Upland Irrigation Schete 94 Naururu Scheme 96 Marwa Scheme 100 The Coatal Plain of th,?. Wami River 101 CHAPTER VIII SOCIAL CONSIERATIONS 1.2LTCATIONS FOR 103 SETTLET,TNT Introduction 103 Main Findings 104 Application of the Main Findings to 106 Irrigation Settlement C7APTER IX AGRONOMIC INVESTIGATIONS 109 1, Current Land Use 109 Experimental Work 113 Pilot Irrigation Areas 121 Priorities for Irrigation Development 122 page No. CHAPTER. X RKETING CONSIDERATIONS FOR THE 125 NI AND KLEE IRRIGATION SCHEMEf Introductiou 125 Cost of Overheads fOT Irrj.con Do-relopment 127 Returns cud Variable Coss of Production 128 Other Consiaara-Uoym 131 Dairy Prodlaction 133 Crop Rotatiou 133 : 'EMENT AND DEVELOPYI, T OF rah; PROPOSED 137 GA ON AT KAHE Kale 137 Miwaleni Upland 140 APPENDIX I PLAN OF OPERATION 141 APPENDIX II LIST OF-STAFF ENGAGED AT VARIOUS PERIODS ON 155 TEE PROJECT APPENDIX III MONTHLY ANNUAL DISCHARGES IN ACRE FEET 159 RIVER WAMI AT MANDERA STATION No. 102 APPENDIX IV HEADQUARTER STAFFING 161 APPhIVDIX V PROPOSE7 ST* 1 LOCKS 163 APPENDIX VI BIBL7 1.65 APPENDIX VIILIST 07 SPECIIILIS TS .A.3a CO7SULTAN TS REPORTS 167 PB.0.0IICIT:D 11_9111 PROrrf?O 'I! OP fraATI 0 NS 3.1i reLrE P i I Lt.7.1:127,? S:CliS '11:q:,..1)/7,: Acreages and 36 2 SamnoA: Aroar AAJAÌ-,veel Pahgcmi and. Jaml racAms Irmigairion Clasmes cm.6, Aorocg,.A 54 Wteen gounjy 1.-:a.nSclA at Selected Sites 59 'rhohn;3) 4 Summo.f,mod CiAblat j Jg.0 Aon thc, 65 Jow®: kombi Pamgani and the -;.nn Ua07.7 5 Evauai-,iolt L0,360t,:,iAprossed ih Yrches per 65 Month CompoThd rf;,t3iVepAan°:,1 :51co2oula and Measured 2row L!,,o,,, i; ! PacA) 6 Stifilway;\, co7 VJO T,i(-Amoo.-6. -Pcn...j'.1.:13ztion 68 Developwnt in tb.e Paugani River Basin (in aovr,) ):o..) 7 RiverLawiArnima'l Modiargo. in Acre Feet at 68 Eindera Cacgim-r; Ation 8 Estimate J.:7 Co:,t 61)poI am o 74 Coo.lrno2 9 Ar cnc:. Loss in the-hgani , 77 10 ".;''is yam; 81 , 11 ,; "' 83 ' 6.1 1.¡; 0111 Off, ii 1") 12 -; Aor ;Ao Power 84 VT,toul 5,71v,1 CLii Table No. Page No,, 13 Estimated Cost of Layout for Surface 94 Irrigation Kahe 14 Estimated Cost of Layout for Overhead 95 Sprinkler Irrigation Kahe 15 Estimated Cost of Layout for Surface 96 Irrigation Miwaleni Upland Irrigation Scheme (1966.5acres) 16 Yield of Maize Varieties from Bulk 114 Plantings (lbs/acre) 17 Yield of Grain of Four Varieties of 115 Sorghum (lbs/acre) T OF FIGURES Page No. No. Frontispiece: Location of Tanzania in Africa PanganiWami River Basins 1 PanganiRiver Basin Location of Irrigation 3 and Hydroelectric Power Investigations WamiRiver Basin Location of Irrigation and 5 Hydroelectric Power Investigations Areas of Topographic and Soil Surveys of 9 PanganiWami River Basins in Tanzania 4 Location of Soil Surveys in the Pangani Head 37 water Region 5 Irrigation Class Map of the Miwaleni Spring 39 Area 6 Irrigation Class Map of the Kahe Area 43 7 Location of Soil Surveys in the Middle Pangani 45 Region 8 Irrigation Class Map of the Naururu Area 49 9 Location of Soil Survey in the Wami Coast 51 Region 10 Mean Annual Rainfall of Pangani River Basin 57 11 20 Percent 'epobabill',,y Annual Rainfall of 61 Pangani kiverBaHin 12 10 Percent Probability Annual Rainfall of 63 Pangani River Basin 13 Arcas of Suggested